[
https://issues.apache.org/jira/browse/HDFS-14610?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Anu Engineer reassigned HDFS-14610:
-----------------------------------
Assignee: Paul Ward
> HashMap is not thread safe. Field storageMap is typically synchronized by
> storageMap. However, in one place, field storageMap is not protected with
> synchronized.
> -----------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-14610
> URL: https://issues.apache.org/jira/browse/HDFS-14610
> Project: Hadoop HDFS
> Issue Type: Bug
> Reporter: Paul Ward
> Assignee: Paul Ward
> Priority: Critical
> Labels: fix-provided, patch-available
> Attachments: addingSynchronization.patch
>
>
> I submitted a CR for this issue at:
> [https://github.com/apache/hadoop/pull/1015]
> The field *storageMap* (a *HashMap*)
> [https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java#L155]
> is typically protected by synchronization on *storageMap*, e.g.,
> [https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java#L294]
> [https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java#L443]
> [https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java#L484]
> For a total of 9 locations.
> The reason is because *HashMap* is not thread safe.
> However, here:
> [https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java#L455]
> {{DatanodeStorageInfo storage =}}
> {{ storageMap.get(report.getStorage().getStorageID());}}
> It is not synchronized.
> Note that in the same method:
> [https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java#L484]
> *storageMap* is again protected by synchronization:
> {{synchronized (storageMap) {}}
> {{ storageMapSize = storageMap.size();}}
> {{}}}
>
> The CR I inlined above protected the above instance (line 455 ) with
> synchronization
> like in line 484 and in all other occurrences.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
